1. Field of the Invention
The present invention relates to a head protection airbag device equipped with an airbag having a configuration that is stored in a folded state on an upper edge of a window (a side window) on a vehicle interior side of a vehicle side surface, and is deployed and inflated downward at the time of inflow of an inflating gas to cover the vehicle interior side of the window.
2. Description of the Related Art
In related art, as a head protection airbag device, an airbag has been configured to include a gas inflow portion capable of being inflated to separate a vehicle inner wall portion and a vehicle outer wall portion by introducing the inflating gas, and a non-inflow portion which does not introduce the inflating gas by coupling the vehicle inner wall portion and the vehicle outer wall portion (for example, see JP-A-2012-201312). The gas inflow portion includes, as an inflation part for introducing the inflating gas and inflating, a main inflation portion that covers a vehicle interior side of a window (a front side window), an end-side inflation portion which is disposed on a front end of an end portion in a front-rear direction of the airbag in adjacent to the main inflation portion and is disposed on the downstream side of the inflating gas from the main inflation portion, and a supply passage portion which is disposed atom the front-rear direction of the upper edge of the airbag to supply the inflating gas to the upper side of the main inflation portion. Further, the non-inflow portion includes a peripheral portion disposed on the peripheral edge of the gas inflow portion, a closing portion which is disposed to regulate the thickness of the inflation portion of the gas inflow portion or partition the inflating sit and a plurality of mounting pieces which are disposed to extend upward on the upper edge of the airbag and is mounted to the upper edge of the window.
In the airbag of the head protection airbag device, a boundary closing portion as the closing portion is disposed between the main inflation portion and the end-side inflation portion of the airbag at the time of completion of inflation so as to partition the main inflation portion and the end-side inflation portion, and the boundary closing portion is provided with a distribution port capable of allowing the inflating gas from the min inflation portion to flow to end-side inflation portion, between the upper edge and the lower edge of the peripheral portion (for example, see JP-T-2001-505846 and JP-A-2010-215096).
In the head protection airbag device in the related art, however, in a case where the airbag is configured that the main inflation portion and the end-side inflation portion are partitioned by the boundary closing portion, and the inflating gas from the main inflation portion via both sides of the upper and lower distribution ports of the boundary closing portion inflates the end-side inflation portion, the end-side inflation portion tends to complete the inflation later than the main inflation portion. When the end-side inflation portion completes deployment and inflation much later than the min inflation portion, at the time of oblique collision of the vehicle when the occupant moves in the vehicle exterior side direction obliquely forward of the vehicle, s not possible that the end-side inflation portion can properly hold the occupant. Additionally, when the end-side inflation portion completes deployment and inflation much later than the main inflation portion, there is a concern that, in the vehicle where a peripheral airbag such as a driver's seat airbag, a passenger's seat airbag, and the like is disposed and inflated on the vehicle interior side of the end-side inflation portion, due to the interference of the inflated peripheral airbag, the end-side inflation portion is not smoothly deployed and inflated to lower edge.